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04-30-2015, 12:43 PM
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#1 |
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Recycler
Join Date: Sep 2002
Location: Mill City Oregon
Posts: 88
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HEI swap
I'm sure it's been asked, sorry to ask again but couldn't get search to work.
Looking for tips and tricks to swapping in a HEI into my 72 C20. Thanks
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72 C20 with a 350. Previous owner swapped the 4 speed for a 700R4 auto. I'm retired and volunteer at state and national parks. I spend summers in Oregon. Found this truck for $800 and offered $600. Paid for it with $$ made from recycling bottles and cans. Oregon pays .05 per can/bottle. Now doing restification with recycled parts purchased with recycling $$. |
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04-30-2015, 01:09 PM
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#2 |
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Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,418
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Re: HEI swap
It's not complicated at all and well worth the time to do it. I just installed a stock GM HEI, new 8mm wires and AC plugs. You will need 12 V keyed power, run a new wire direct to keyed "on" from fuse block. Afterward's my 350 starts on first try, idles better and improved mileage. Also cleans up the area behind carb . Buy quality parts and you will love the results....
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71 C-20 07 Magnum RT AWD |
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04-30-2015, 01:13 PM
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#3 |
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Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,418
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Re: HEI swap
Forgot to add, open up plug gap to 45 , HEI produce hotter spark. Hope this helps, best modification I have done for the expense evolved .
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71 C-20 07 Magnum RT AWD |
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04-30-2015, 01:56 PM
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#4 |
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Recycler
Join Date: Sep 2002
Location: Mill City Oregon
Posts: 88
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Re: HEI swap
Where do I get the power from?
Also HEI has three wires with a connector.
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72 C20 with a 350. Previous owner swapped the 4 speed for a 700R4 auto. I'm retired and volunteer at state and national parks. I spend summers in Oregon. Found this truck for $800 and offered $600. Paid for it with $$ made from recycling bottles and cans. Oregon pays .05 per can/bottle. Now doing restification with recycled parts purchased with recycling $$. |
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04-30-2015, 01:58 PM
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#5 |
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20' Daredevil (Ret)
 
Join Date: May 2003
Location: Jefferson State
Posts: 13,810
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Re: HEI swap
^ Agree with everything posted above. Only thing I can add is to use 12 ga. wire for the new hot lead. That said, 14 ga. will probably work just fine, and 10 ga. is overkill, stiffer heavier and more trouble to deal with, imho.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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04-30-2015, 02:00 PM
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#6 |
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Registered User
Join Date: May 2014
Location: PA
Posts: 1,417
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Re: HEI swap
Replace your original points distributor power wire with a new 14 gauge wire. The original wire won't work because it is a resistance wire designed to drop the voltage to about 7-8 volts that was required for points.
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1967 C10, LWB, 250, Powerglide, PS, PB, 3/4 STATIC DROP |
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04-30-2015, 02:04 PM
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#7 |
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20' Daredevil (Ret)
Join Date: May 2003
Location: Jefferson State
Posts: 13,810
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Re: HEI swap
Not sure about the three wires. I used a late-Seventies GM unit. Got power from the right side of the fuse block. There are two male spade lugs marked IGN UNFUSED. Make sure it's hot only when the key is in the "ON" and "START" position.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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04-30-2015, 02:12 PM
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#8 |
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Registered User
Join Date: Jan 2009
Location: Calgary, AB
Posts: 1,181
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Re: HEI swap
You will need at least 2 plugs.
The 3 wires you see with bare ends plugs into the same spot as the bat+ and tach signal except its behind that. That is a pretty hokey distributor that doesn't have any plugs. |
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04-30-2015, 02:41 PM
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#9 |
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Registered User
Join Date: Feb 2011
Location: Modesto, CA
Posts: 2,189
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Re: HEI swap
I prefer clean wiring so i removed the old power wire and replaced it. You can pick up Packard 57 spade terminals that plug into the factory harness from NAPA. Rewrapped the harness with the correct wrap and bingo: factory look with hei.
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